Fuel injection system and distributor valve therefor



u 7, 1968 R. J. MADDALOZZO 3,398,730

FUEL INJECTION SYSTEM AND DISTRIBUTOR VALVE THEREFOR Filed Oct. 51, 1966 5 Sheets-Sheet 1 Aug- 2 1968 R. .1. MADDALOZZO FUEL INJECTION SYSTEM AND DISTRIBUTOR VALVE THEREFOR Sheet 2 Filed Oct. 51, 1966 United States Patent 3,398,730 FUEL INJECTION SYSTEM AND DISTRIBUTOR VALVE THEREFOR Raymond J. Maddalozzo, Chicago, Ill., assignor to International Harvester Company, Chicago, 11]., a corporation of Delaware Filed Oct. 31, 1966, Ser. No. 590,779 Claims. (Cl. 123-139) ABSTRACT OF THE DISCLOSURE A rotary distributor valve driven in timed relation with the engine supplies a plurality of individual lines, each connected with a fuel injector nozzle from an inlet connected with a source of fuel under pressure. During operation of the valve the individual lines are sequentially subject to full pressure to charge an accumulator chamher in each nozzle, then to drain pressure to initiate injection from the nozzle and then an intermediate pressure to terminate injection. The period between initiation and termination is determined by a governor.

This application describes certain of my improvements on the fuel injection structure of Heintz U.S. Patent No. 3,187,733, the disclosure of which is incorporated in entirety herein by reference.

My invention relates to the fuel injection system of a compression ignition engine, and specifically to a central control or distributor valve which coordinates the operation of the injection system. It more specifically relates to a port-type rotary valve common to the injectors for all cylinders for supplying and operating them in sequence, each to deliver a metered quantity of fuel injected over the course of an accurately predetermined number of degrees of rotation of that valve.

An object of the present invention is the provision, in a multinozzle fuel injection system for an engine, of a rotary distributor valve connected in common to all nozzles, and hydraulically actuating them so that the nozzles inject fuel under high pressure from their accumulators for the right time and duration of injection.

A further object in line with the preceding objective is to provide a system of multinozzles having a rotary distributor valve therefor, and being hydraulically operated by the latter by a rapid pressure-Wave actuation principle affording immediate response of each nozzle in initiating and stopping its injection.

Another object of the invention in line with the preceding objective is the provision of a rotary distributor valve for a plurality of accumulator type injection nozzles, the valve being internally ported in a manner for not only causing each of the nozzles in rotation to discharge precisely metered fuel from and at the high pressure of the accumulator of that nozzle, but also insuring that the accumulators of all nozzles not momentarily engaged in the fuel injection phase of the cycle freely communicate through the valve with a source of rail pressure. The latter nozzles are thus afforded a comparatively long recharging or replenishing phase in the cycle, so that fuel will be stored in the accumulator of each nozzle in about the same quantity as injected during the preceding injection phase of the cycle of that nozzle.

In an accumulator type fuel injection system employing differential type nozzles, a disadvantage exists in adapting the system to high speed, multicylinder engines wherein the time interval is very short for distributing and injecting metered quantities of fuel to and from the various nozzles in succession. A conventional distributor valve, provided in common to all nozzles, encounters ice stringent conditions and ditficulties in the effort to cause injection in each nozzle to start and to stop at precisely the right times, and under varying loads, and throughout the entire range of speeds of the high speed engine.

This invention materially reduces or substantially eliminates the foregoing difliculties through provision of the present injection system and distributor valve therefor, and a novel pressure-Wave disseminating, internal porting arrangement in the distributor valve in the system, all as will now be explained in detail.

Features, objects, and advantages will either be specifically pointed out or become apparent when, for a better understanding of the invention, reference is made to the accompanying drawings which form a part thereof, and in which:

FIGURE 1 is a left side elevational view of a fuel injection system as applied to a compression ignition engine and embodying the present invention;

FIGURE 2, being partly schematic, is a longitudinal section view of the distributor valve and one of the associated nozzles in the system of FIGURE 1;

FIGURE 3 is a rear end view, in elevation, of the distributor valve shown in FIGURES 1 and 2;

FIGURE 4 is taken along the section lines IVIV of FIGURE 2 and is a section showing the valve adjusted for idling the engine;

FIGURE 5 is somewhat similar to FIGURE 4, but shows all grooves;

FIGURES 6, 7, 8 and 9 follow FIGURE 5 in a sequence showing only the fuel injection phase of an entire inject-refill cycle for one engine cylinder; and

FIGURES 10, 11, 12 and 13 are schematic developed views, taken generally along the section lines, XIII XIII of FIGURE 2 so as to show the injection phase of a cycle from another viewpoint.

In the present multiinjector system, the accumulator chamber in each injector receives fluid under rail pressure over a long period of the cycle time thus storing all of the potential energy in the accumulating fluid so collected. Opening of an injector nozzle releases considerable hydrostatic energy causing the fluid to escape under high pressure and in a metered amount which must spray out in an exceptionally short period of time. Each injector, following injection, is immediately connected on recharge by the distributor valve. A six-cylinder compression ignition engine is herein illustrated to show the adaptability of the present valve to multicylinder work, but for the sake of brevity only the cycle for one injector nozzle is specifically described.

FIGURE 1 An injection system for the engine 20 includes injector nozzles 22, one for each cylinder which are not shown. The nozzles 22 inject according to the engine firing order and each has a single supply-control fuel delivery line 24 between it and one of a plurality of equally circumferentially spaced apart points on a rotary distributor valve 26 which includes a housing designated 26a in FIG. 2. A gear-driven input shaft 28 is mounted in the valve 26 so as to provide a speed which is one-half of the engine crankshaft speed and the rotational angle is accurately phased to the position of the pistons, not shown, in the engine 20.

A small-capacity drain line 30 leading from the valve 26 returns fluid, mostly leakage fluid, to a fuel tank 32 in the system. A pump line 34, drawing fluid from the fuel tank 32, includes an exceptionally high pressure pump 36 driven by the engine, an accumulator 38 which collects the fluid under the high or rail pres-sure, and a supply fitting 40 at the end of the line 34 at which it delivers rail pressure to the distributor valve 26.

3 FIGURE 2.--Nozzle structure Internally of each nozzle 22, there is an accumulator chamber 42 at the front surrounding a poppet valve assembly generally indicated at 44. The poppet assembly 44 includes a needle 46 which rests on a spray jet seat 48 and which has an enlarged head 50 of which the upper portion 52 serves as a piston in a central longitudinal passage 54 within the nozzle. A se'mispherical member 50a surrounding the head 50 rests against a snap ring 50b on such head. A heavy, valve-seating spring 56 within the accumulator chamber 42 acts between a shoulder 56a in the nozzle and a spring seat 56b on the member 50a in a direction constantly to bias the needle 46 in closed position on the seat 48.

Within an upper portion of the central passage 54, a poppet check valve 58 establishes one-way communication between that passage and a rear section 60 of the accumulator chamber. An offset, longitudinal passage 62 within the nozzle interconnects the rear section 60 with the main portion of accumulator chamber 42. A cap 64 at the front end of the injector 22 and a headcap 66 at the head or rear end seal the injector against leakage.

The fuel delivery line 24 for each nozzle is connected thereto by a banjo fitting 68 which establishes communication with the central passage 54 through a branch 54.1 thereof.

FIGURES 2 and 3.--Distribut0r structure A bevel gear 70, forming the last step of a stepped gear train driven by the engine, is axially adjustably carried by the valve input shaft 28 on a set of straight splines 67. The stepped gear train further includes a wide bevel pinion 71 which is in a fixed position on a driving shaft 69 therefor and which pinion 71 is in continuous mesh with the bevel gear 70. A timing adjustment fork 73 schematically indicated within a groove on the bevel gear adjusts the rotational and axial position of the gear 70 by causing the gear to slide along the teeth of the pinion 71. The timing is advanced or retarded depending upon whether the gear 70 is retarded pursuant to axial advancement in the direction of the arrow toward or into the advanced position shown by the broken lines 70a, or axially withdrawn into the retarded position as shown by the solid lines.

The valve housing 26a rotatively supports the shaft 28. Said valve housing includes a supporting and attachment cap 72 at the front end adjacent the gear 70 and a rear cap 74 at the opposite end.

A sleeve-shaped rotor 76 is mounted within the valve housing and carries governor flyweight parts 78 which are at one end of the rotor and which are included in a speed control mechanism. The rotor 76 is driven by a connection 80 formed of interlocked jaws between it and the input shaft 28. The rotor 76 supports a relatively fixed inner stator part 82.

The inner stator part 82 cooperates with the rotor 76 in a mechanical manner, and in that connection the stator part 82 is rigid with an axially extending shaft 84. For purposes of controlling axial adjustment of the stator part 82, the shaft 84 carries a governor cup 86 which restrains movement of the fiyweights 78 radially outward of such cup which is included in the governor mechanism in a manner to increase fuel when the ilyweights 78 collapse and the governor cup 86 accordingly moves with the shaft 84 in the direction of the arrow indicated in FIGURE 2.

A governor spring 88 is schematically shown between the end cap 74 and a timing plate 90 and serves to bias the shaft 84 in the fuel increasing direction. An adjustment fork 92, schematically shown, can be moved by the operator in a direction tending to collapse the spring 88 and thus advance the governor condition from idle setting to a full power setting.

The governor mechanism is schematically shown herein for ease in understanding. In actual practice, various idling, full power, and overload control devices of conventional construction will be provided to avail precise control.

The rotational position of the shaft 84 is controlled by the timing plate 90, which carries a transverse lug 94. Two opposed bolts 96 which are threaded through the end cap 74 clamp the lug 94 in various angular positions to produce the timing desired. Timing is advanced (FIG- URE 3) by releasing one of the bolts and tightening the opposed bolt, moving the lug 94 in the direction of the arrow.

A center land 98a on the inner stator part 82 defines, between it and an end spool 98, a first stator chamber 100. The center land defines, between it and another end spool 102, a second stator chamber 104. The outer periphery of the rotor 76 is grooved to form a cul de sac or rotor chamber 106 and is further grooved to form a pressure chamber 108 separate from chamber 106 and of which a portion is in alignment with the chamber 106 circumferentially of the stator 82, FIGURES 2 and 4, and which portion is of sufiicient circumferential extent to concurrently register communicatively with all but one of the supply-control line ports 110.

Rail pressure is maintained in pressure chamber 108 by the pump line 34, and this pressure is communicated from chamber 108 through a passage 112 to the first stator chamber and thence into helical metering grooves 120 which successively communicate radially through a stator port 122 with the cul de sac 106. The pressure chamber 108 which is maintained by the pump concurrently supplies the rail pressure through all but one of the passages and thence through all but one of the supply-control lines 24 to all injectors except the one which is then being controlled to deliver a metered quantity of fuel to its associated engine combustion chamber, in a manner hereinafter explained in detail.

Periodically, the rotor chamber 106 is opened to drain in a path including a spill port 114, individual straight spill grooves 116 formed on the inner stator part 82 parallel to the axis thereof, the second stator chamber 104, a connecting radial passage 117, an annular groove 118 formed on the rotor 76, and the drain line 30 which is at low pressure. At other times the revolving rotor chamber 106 communicates with the successive delivery line port 110 each connected to an associated nozzle 22 by an associated delivery line 24. During the last portion of this communication through a delivery line port 110 with each nozzle, the first stator chamber 100 also communicates with the rotor chamber 106 through a path including an associated one of the helical metering or pressure grooves 120 and the metering port 122 which then registers with such metering groove.

An examination of FIGURES 11 through 13 will make it apparent that when the governor mechanism slides the stator part 82 in the fuel increasing direction indicated by the arrow in FIGURE 2, there will be a longer interval of time between the start of registry of the revolving and then pressure-relieved rotor chamber 106 and a delivery line port 110 (negative injection-causing pressure wave thus incurred in line 24 to the associated nozzle to open the nozzle poppet) and the start of registry of the port 122 of chamber 106 with a metering or pressure groove 120 (positive poppet-reseating wave thus incurred in line 24, terminates injection). The converse is similarly true, wherefore the metered quantity of fuel is decreased as a direct function of movement of the inner stator part 82 by the governor mechanism in a direction to the right as viewed in FIGURE 2.

FIGURE 4.Metering and recharging If the width of rotor chamber 106 is considered to extend in the axial direction of the sleeve or rotor 76, then said chamber in the lengthwise sense is comparatively short, i.e., it has minor angular extent annularly, amounting only to about 32.5 in the illustrative embodiment of the invention. The groove-shaped pressure chamber 108, though shallower, is a comparatively long one in terms of angular extent, amounting to 300 in such illustrative embodiment of the invention. The significance of this is that the pressure chamber 108 is always keeping five of the deliveny line ports 110 (angular spacing 60 apart) charged or charging with rail pressure, insuring that their respective nozzle accumulator chambers 42 are completely refilled prior to each injection portion of their operating cycle.

The rotor 76 is shown in FIGURE 4 axially adjusted for engine idling. In that position of adjustment, an equalizing edge 124 of the advancing rotor chamber 106 uncovers the next delivery line port 110 at a point which can occur as little as 4 ahead of the point at which the port 122 communicating with the rotor chamber 106 uncovers a poppet reseating edge 126 of the pressurized metering groove 120. The two points referred to establish the start and termination of injection of a metered quantity of fluid, as will now be more fully explained.

FIGURES 5, 6, 7, 8 and 9.-Injecti0n phase of the cycle In FIGURES 5, 6, 7, 8 and 9 the inner stator part 82 is illustrated in the full load position, which is between the engine idling position of FIGURE 4 and an overload position assumed by the valve in FIGURE 2. Before the start of the injection phase of each injector cycle, the cul de sac or rotor chamber 106 undergoes three changes of internal pressure, namely from a higher pressure to a drain level or residual pressure, thence to an equalizing or high pressure, thence to a poppet reseating pressure which is above the high pressure, and thereafter it reaches the higher pressure first referred to which is a pressure between the poppet reseating pressure and rail pressure. Actually the chamber 106 never attains full rail pressure, which is the highest in the system.

On the way to the delivery line port 110 beginning in FIGURE 5, the far port 114 which communicates with the rotor chamber 106 is about to encounter one of the straight spill grooves 116. At this time, that is, just before such encounter, the chamber 106 is at the higher pressure referred to, whereas the delivery line 24 and the delivery line port 110 continue communication with the pressure chamber 108 and with the accumulator chamber in the nozzle associated therewith to cause this accumulator chamber to be fully charged at rail pressure. When the far port 114 encounters groove 116 the pressure in chamber 106 will be diminished to said drain or residual pressure which will prevail into the FIGURE 6 position.

In FIGURE 6, the equalizing edge 124 of the rotor chamber 106 has advanced and is about to uncover the delivery line port 110, the chamber 106 with its pressure reduced to drain pressure having at this time either entered into sequestration or started to enter into sequestration from the spill groove 116 due to rotor rotation. In the latter connection, it is sometimes desirable if not essential to provide for an overlap so that the delivery line port 110 and the spill groove 116 intercommunicate through the chamber 106 for a short overlap period to insure that the nozzle pressure drop is suflicient to start injection.

At and after the point at which the equalizing edge 124 uncovers the delivery line port 110, the fluid in the delivery line and inside the nozzle bore 54 is diminished to an equalizing pressure common with that in the rotor chamber 106. Depending upon the referred to port-andgroove overlap being designed into the system or not, the equalized pressure can range upwardly from slightly above the drain pressure level, to a value only slightly below the initial nozzle pressure (rail pressure) because of the small capacity of the rotor chamber. The equalized condition is illustrated in FIGURE 7. The resulting diminution of pressure provided for in the nozzle bore 54, allowing it to reach the so-called equalizing pressure, is always sufficient to enable the pressure in nozzle accumulator chamber 42 to prevail over the pressure in said bore 54, thereby lifting both the valve needle head 50 and the needle 46 so as to commence fuel injection.

Continued rotation of the ports in the direction of rotation indicated by the arrow in FIGURE 7 toward the FIGURE 8 position, causes the near port 122 leading into the rotor chamber 106 to uncover the poppet reseating edge 126 of the pressure or metering groove 120. Fluid flow into the rotor chamber 106 establishes poppet reseating pressure therein, thereby terminating injection by the associated nozzle.

In FIGURE 8, it is seen that the rotor chamber 106 by progressive movement is blocked from the metering groove 120 and will be blocked from the delivery line port 110, in that order, leaving the chamber 106 and the delivery line each sequestered at the higher pressure referred to. The trailing or sequestering edge of the chamber 106 blocks it from the port as illustrated in FIGURE 9.

FIGURE 9 shows the valve parts shortly after completion of the injection phase of the cycle for the nozzle referred to, the pressure chamber 108 approaching the port 110 in the direction of the arrow in order to communicate and thereby recharge the depleted pressure in the nozzle to rail pressure, in the process of refilling the accumulator chamber therein. The far port 114 connected to the rotor chamber 106 is about to come into registry with the next spill groove 116 for reducing the chamber 106 back to drain level or to the aforesaid residual pressure somewhat below rail pressure in the nozzle accumulator 42 and bore 54. Thus, the valve parts advance 60 in progressing from the FIGURE 5 showing to the FIGURE 9 showing, being readied to undertake the injection phase of the cycle for the next nozzle whose delivery line 24 is indicated in broken lines in FIGURE 9.

FIGURES 10, 11, 12 and ]3.Energy and fluid transfer The volume of the rotor chamber 106 is very small and the pressure differences available for charging and for depressurizing it are very high. For that reason the time lag between successive port communications with this rotor chamber and the respective consequential establishment therein ofthe successive pressure values for causing discharge of metered quantities of fuel from the nozzles is so slight as to be practically instantaneous.

FIGURE 10 shows a transition period of the valve parts intervening between their relative position shown in FIGURE 5 and their relative position shown in FIGURE 6. Registration between the straight spill groove 116 and the far rotor chamber port 114 produces primarily an energy transfer, because the chamber 106 retains just about the same quantity of fuel at the higher pressure and at the drain pressure.

FIGURE 11 shows the valve parts in an intervening position from their relation shown in FIGURE 6 and their relation shown in FIGURE 7. The illustrated registration between the rotor chamber 106 and the delivery line port 110, due to uncovering of the latter by the equalizing edge 124, results principally in an energy transfer, because the chamber 106 represents a dead end for the delivery line and holds approximately the same quantity of fluid at the drain level pressure as at the equalizing pressure mutually reached by the delivery line and the rotor chamber 106. This energy transfer is in the form of a negative pressure wave which is immediately communicated to the nozzle for opening the poppet and initiating injection.

FIGURE 12 illustrates the valve parts in a position intervening between their relationship as shown in FIG- URE 7 and their relationship as shown in FIGURE 8. Registration between a pressure or metering groove 120 and the near port 122 connected to the rotor chamber 106 results principally in substantially only an energy transfer, because the poppet reseating pressure is restored by substantially the amount of fluid which originally transferred from the delivery line into the rotor chamber 106 so as to equalize the pressures.

FIGURE 13 shows the valve parts in the. recharge relation which occurs just subsequently from the position shown in FIGURE 9. Commencement of registration between the delivery line port 110 and the pressure chamber 108 on the rotor starts recharging of the nozzle accumulator chamber 42, which continues throughout the intervening degrees of rotation of the value until the chamber refills completely with a replenishing amount of fluid equal to the amount rejected.

FIGURE 2.Nzzle cycle Each negative pressure wave which is communicated to a nozzle to initiate injection allows the pressure in the accumulator chamber 42 to partially collapse the spring 56 in the nozzle by forcing the needle head 52 and other parts of the poppet assembly 44 upwardly as viewed in FIGURE 2. The needle 46 moves from the poppet spray jet seat 48 and the internal pressure of the expanding fuel causes it to inject and, at the same time, the pressure acts against the opening needle 46 and the portion of the needle head 50 exposed in an annulus 127 in the fluid passage, so as to fully open the nozzle orifices 128 for fuel jet discharge.

The subsequently following positive pressure wave through the bore branch 54a increases the pressure on the upper end of the needle head 50, allowing supplementing the force of the spring 56 to reseat the needle 46 and close the poppet seat orifices 128.

During recharge, rail pressure existing in the passage 54 within the nozzle 22 keeps the spring-pressed check valve 58 off its seat until fluid flowing therethrough causes the accumulator chamber 42 and the rear section 60 thereof to attain rail pressure. During this period, the needle 46 remains seated.

EXAMPLE Following is an example of values for the diesel fuel system foregoing:

Number of engine cylinders 6.

Engine operation 4 stroke cycle.

Rail pressure developed by pump 36 20,000 p.s.i.

Number of helical slots or grooves 120 6.

Number of straight slots or grooves 116 6.

Injection angle range 0-l9 of valve rotation.

It is apparent from the foregoing that the parameters of injection are precisely controlled over a wide range. The precise time of injection, to occur as illustrated in FIGURE 11, is appropriately set relative to engine piston motion by angularly adjusting the gear 70 in the range illustrated in FIGURE 2, and by equally angularly adjusting the timing plate 90 in the range illustrated in FIG- URE 3. The desired negative pressure wave is communicated to the nozzle instantaneously with opening of the port 110 to the rotor chamber 106 and there is no inertia problem.

The precise cut-off of injection, to occur by reapplication of pressure as illustrated in FIGURE 12, is appropriately set relative to engine piston motion by longitudinally adjusting the position of the metering grooves 120. The desired positive pressure wave is communicated to the nozzel instantaneously with opening of the port 122 to the groove 120 and there is no inertia problem.

I claim:

1. A liquid fuel delivery distributor valve for cyclically controlling the fuel delivery between a source of fuel under high pressure and an accumulator type elastic pressurewave actuated fuel injection nozzle of an operative compression-ignition internal combustion engine comprising:

(a) an outer stator member having a first passage communicatively connected to said source and a second passage communicatively connected to said nozzle,

(b) a rotatable valve element having a rotor chamber disposed therein and driven by said engine in phased relation, said chamber being positioned in relation with said second passage to alternately register and deregister with respect thereto,

(0) an inner stator member disposed in said valve element,

(cl) first means in the inner stator member and said valve element adapted to reduce the pressure in said chamber during a cycle-initiating first operational period,

(c) said chamber registering with said second passage during a subsequent second operational period for inducing an elastic negative-pressure wave to actuate said nozzle thereby commencing injection of fuel under pressure into said engine,

(f) second means in said inner stator member and said valve element positioned to communicate said first passage with said rotor chamber while such rotor chamber is in communication with said second passage during a subsequent third operational period for inducing an elastic positive pressure-Wave in said second passage to de-actuate said nozzle after a predetermined quantity of fuel has been injected into said engine,

(g) and a third means in said valve element positioned to communicate said source with said second passage following deregistration of the rotor chamber with respect to said second passage and during a final operational period of said cycle for charging fuel into the accumulator of said nozzle whereby said distributor valve controls fuel delivery and hydraulic actuation of said injection nozzle in phased relation through said second passage for operating said englue.

2. The invention of claim 1, the first means comprising a spill groove on the inner stator member, and a spill port in the valve element connected to said rotor chamber and positionable in registrable relation with the spill groove during said cycle initiating first operational period.

3. The invention of claim 2, the second means comprising a pressure groove on the inner stator member, and a second port in the valve element connected to said rotor chamber and positionable in registrable relation with the pressure groove during said third operational period.

4. The invention of claim 3, said pressure and spill grooves formed on the inner stator member comprising, respectively, a metering groove which is a helical groove and an equalizing groove which is a straight groove.

5. The invention of claim 4, said inner stator member and said valve element having means of effecting relative rotational adjustment and making relative longitudinal adjustment therebetween to adjust injection timing and fluid metering.

References Cited UNITED STATES PATENTS LAIURENCE M. GOODRIDGE, Primary Examiner. 

